Blumea 64, 2019: 195–213 www.ingentaconnect.com/content/nhn/blumea RESEARCH ARTICLE https://doi.org/10.3767/blumea.2019.64.03.01 A revision of Scleria (Cyperaceae) in Madagascar J. Galán Díaz1, K. Bauters2,3, L. Rabarivola4, M. Xanthos5, P. Goetghebeur3, I. Larridon3,5 Key words Abstract A taxonomic revision of the genus Scleria (Cyperoideae, Cyperaceae) in Madagascar is presented. Herbarium specimens have been examined and 422 identified to species level. Our results recognise 25 species conservation of Scleria from Madagascar, plus an additional heterotypic variety. Eight species are endemic to Madagascar, two Cyperaceae are near endemic, eight taxa are also found on mainland Africa, and eight are widespread tropical taxa. Scleria endemic species achtenii is reported from Madagascar for the first time, and S. rosea is accepted at species level instead of being identification key considered as a synonym of S. trialata. Distribution maps, conservation assessments, and notes on synonymy, Madagascar ecology and ethnobotany are provided. Fourty-seven names are typified. Three rare endemic species: S. andrin- revision gitrensis, S. madagascariensis and S. perpusilla, are assessed as threatened; and a recently described species, Scleria S. ankaratrensis, is indicated as Data Deficient. The most species-rich infrageneric taxa, sections Hypoporum, Abortivae and Foveolidia include 18 taxa in total, and showed strong differences in habitat preference. Published on 23 September 2019 INTRODUCTION Sheaths are sometimes winged, and usually topped by a contra- ligule (Haines & Lye 1983), opposite to the blade. Inflorescences Cyperaceae or the sedge family includes c. 90 genera and 5 500 develop distally and are usually subtended by leafy bracts species of annual and perennial herbs (Govaerts et al. 2019). (Robinson 1966). Flowers are always unisexual and enclosed It is a cosmopolitan plant family, which has its centre of generic by at least three glumes (Haines & Lye 1983). Glumes are spi- diversity in the tropics. However, sedges play a fundamental rally arranged in staminate spikelets, and distichous in pistillate role in the ecology of seasonal and permanent wetlands at all spikelets (Ahumada & Vegetti 2009). Flowers group in spikelets, latitudes. Scleria P.J.Bergius (1765: 142), also known as nut where the pistillate flower is always proximal. There are four rushes or razor grasses, is the sixth largest genus in the fam- types of spikelets in Scleria (Eiten 1976, Ahumada & Vegetti ily with 258 species (Govaerts et al. 2019), it is monophyletic 2009): unisexual, i.e., pistillate or staminate; androgynous; and (Bauters et al. 2016), and the only genus of tribe Sclerieae (sub- subandrogynous, when vestiges of male flowers are found in the family Cyperoideae) (Franklin Hennessy 1985, Muasya et al. form of empty glumes. The inflorescence is a panicle that shows 1998, Hirahara et al. 2007, Simpson et al. 2007, Hinchliff & Roal- different degrees of development in the various subgenera and son 2013, Jung & Choi 2013, Bauters et al. 2016, Semmouri sections of the genus (Ahumada & Vegetti 2009, Bauters et al. et al. 2019). Although most species of Scleria occur in tropical 2016). The inflorescences can be summarised in true panicles Africa, South America and Asia, 35 species are found in North (Fig. 1a–c); truncated, when the main axis is underdeveloped America (Govaerts et al. 2019). A recent study showed that (Fig. 1d–f), and spicate-glomerulate (Fig. 1g–i). The fruit is Scleria can be divided into four monophyletic subgenera a nutlet, smooth or ornamented, subtended by a cupule and (Scleria subg. Browniae (C.B.Clarke) C.B.Clarke, S. subg. frequently surrounded by a hypogynium (Fig. 2). In general, Hypoporum (Nees) C.B.Clarke, S. subg. Scleria and S. subg. Scleria from Madagascar can be classified in two groups. The Trachylomia (Nees) Bauters) (Bauters et al. 2016). first encompasses plants with androgynous spikelets arranged Scleria encompasses herbs with variable habits, from tiny annu- in an inflorescence consisting of a linear spike of distant, ses- als with fibrous roots to perennial climbers more than ten metres sile, spikelet clusters subtended by a short glume-like or foli- long. Perennial habit is achieved by means of a stoloniferous ate bract, and nutlets with a reduced hypogynium. This group rhizome or tubers, and certain species develop aerial adventi- of species conforms to Scleria subg. Hypoporum (Bauters et tious roots at stem nodes as an adaptation to flooded habitats al. 2016, 2018, 2019). The second covers plants with lateral (Jacono 2008). Culms are trigonous or triquetrous. Leaves and terminal panicles made of subandrogynous or unisexual are alternate and tristichously arranged, often persistent at spikelets, and nutlets with a conspicuous hypogynium. This the base, and finely serrate at least along the distal third of the group of species conforms to Scleria subg. Scleria (Bauters et margins, rarely smooth. In certain groups, leaves are abruptly al. 2016, 2018, 2019). Although the origin of the hypogynium narrowed down or pseudopraemorse (Bauters et al. 2016). remains obscure (Bauters et al. 2016), the hypogynium is the most informative character to distinguish Scleria species, and 1 Estación Biológica de Doñana (EBD-CSIC), Avda. Américo Vespucio s/n, access to fruiting material is critical for identifying specimens Isla de la Cartuja, Seville, Spain. at infrageneric level (Chermezon 1937, Haines & Lye 1983). 2 Botanic Garden Meise, Nieuwelaan 38, 1860 Meise, Belgium. 3 Ghent University, Department of Biology, Systematics and Evolutionary Very little is known about Scleria pollination and dispersal Botany Lab, K.L. Ledeganckstraat 35, 9000 Gent, Belgium. mechanisms. Wind pollination and hydrochory seem to be 4 Kew Madagascar Conservation Centre, II J 131 B, Ambodivoanjo, Ivandry, common mechanisms. However, S. gaertneri Raddi has been Antananarivo 101, Madagascar. 5 Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, UK; found to be potentially dispersed by frugivorous birds and bats in corresponding author e-mail: [email protected]. the Mexican tropical rainforest (Galindo-González et al. 2000). © 2019 Naturalis Biodiversity Center You are free to share - to copy, distribute and transmit the work, under the following conditions: Attribution: You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). Non-commercial: You may not use this work for commercial purposes. No derivative works: You may not alter, transform, or build upon this work. For any reuse or distribution, you must make clear to others the license terms of this work, which can be found at http://creativecommons.org/licenses/by-nc-nd/3.0/legalcode. Any of the above conditions can be waived if you get permission from the copyright holder. Nothing in this license impairs or restricts the author’s moral rights. 196 Blumea – Volume 64 / 3, 2019 Fig. 1 Main types of inflorescences of Scleria from Madagascar. a. Inflorescence of S. rosea; b. inflorescence of S. trialata; c. inflorescence of S. angusta; d. truncated panicle of S. melanomphala; e. truncated panicle of S. greigiifolia; f. truncated panicle of S. foliosa; g. spicate-glomerulate inflorescence of S. distans; h. panicle of S. hilsenbergii; i. inflorescence of S. lithosperma (a: Ramandimbimanana & Randimbiarison 460; b: Lance 30; c: Mogg 288898; d: Brummit & Singe 232; e: Bosser 15031; f: Raynal 7664; g: Croat 29582; h: Rajaonary 45; i: Frontier-Tanzania Coastal Programme Research Forest 412; all K). — Scale bar: a = 7 cm, b–h = 5 cm, i = 4 cm. J. Galán Díaz et al.: Scleria in Madagascar 197 Fig. 2 Nutlets of Scleria species occurring in Madagascar. a–b. S. madagascariensis; c–d. S. trialata; e. S. baronii; f. S. perpusilla; g–h. S. rosea; i–j. S. hilsenbergii; k–l. S. rutenbergiana; m–n. S. angusta; o. S. andringitrensis (a–b: Rakotozafy 2741; c–d: Lance 30; e. Hoffman 221; f. Decary 7695; g–h: Ranarivelo 282; i–j. Rajaonary 45; k–l: Wilkin 941; m–n: Boivin s.n.; o: Perrier de la Bâthie 14385; all K). The first efforts to explore the sedge diversity in Madagascar Henri Humbert’s ‘Flore de Madagascar et des Comores’. Cher- began at the end of the 19th century with Rev. Richard Baron. mezon (1937) recognised four genera in the tribe Sclerieae: In his ‘Compendium des plantes Malgaches’ (Baron 1906), he Eriospora Hochst. ex A.Rich. (now Coleochloa placed in tribe recognised ten species of Scleria plus Acriulus. For a long time, Trilepidae; Semmouri et al. 2019), Diplacrum (tribe Bisboeck- the genus Acriulus Ridl. (described with 3 species; Clarke 1908), elereae; Semmouri et al. 2019), Acriulus and Scleria. In his was placed either in or close to Scleria. It was finally accepted publication, which constitutes the only revision of Scleria from as the single species Scleria greigiifolia (Ridl.) C.B.Clarke (Kern Madagascar published to date, Chermezon (1937) identified 22 1963, Robinson 1966, Franklin Hennessy 1985), and this has species and two varieties of Scleria, 12 of which were endemic. been recently verified in molecular analyses (Bauters et al. Currently, Govaerts et al. (2019) lists 26 species as occurring 2016). In 1937, Henri Chermezon published the first major revi- in Madagascar, with six endemics, two near-endemic species, sion of the Cyperaceae of Madagascar, which was included in nine species also occurring on mainland Africa, and a further 198 Blumea – Volume 64 / 3, 2019 nine more widely distributed species. Scleria is the second RESULTS largest genus of sedges in Madagascar, and is one of the three genera highlighted in the ‘Catalogue of the Vascular Plants of In total, 422 specimens were identified to species level, 350 of Madagascar’ (2018) for which taxonomic revision is necessary. which were included in the distribution maps. 26 Scleria taxa This study aims to: from Madagascar were identified in the morphological study: 1. update the taxonomy of the genus Scleria in Madagascar; eight endemics; one restricted to Madagascar, the Comoros and and Mayotte; one present in Madagascar and the coast of Natal; 2.